Packaged asphalt



Jan. 30,. 19 6 8 c. ROEDIGER 3,366,233

PACKAGED ASPHALT Filed Sept. 26, 1966 J. C. ROE'D/GER INVENTOR A N AIORNVEV United States Patent 3,366,233 PACKAGED ASPHALT Joseph C.Roediger, Westfield, N.J., assignor to Esso Research and EngineeringCompany, a corporation of Delaware Filed Sept. 26, 1966, Ser. No.581,763

- 9 Claims. (Cl. 20684) ABSTRACT OF THE DISCLOSURE Asphalt is packagedin a mnltilayered or laminated container or encasement of sheeting orfilm of poly alpha olefin having a melt index below about 12 (measuredat 230 C.) and being composed of polyethylene, polypropylene or theplastic or plastomeric copolymer of ethylene and propylene. Thesheetingor film ranges in thickness between about 2 and about 6 mils.

This invention relates to asphalts packaged in a novel way. Morespecifically, the invention relates to the ordinary standard pavingasphalt compositions of commerce and specifically relates to methods ofpackaging the same for shipment from the refineries where such asphaltsare produced to the mixing plants located in relatively close proximityto the sites where such asphalts are ultimately used.

For many years asphalts have been prepared in oil refineries from avariety of specific crudes. For the most part these asphalts are theresidual fractions derived from such crudes as Mexican, Venezuelan,Columbian, California, Mid-Continent, and Talco. The asphalts asproduced at the refineries in molten condition are pumped through steamtraced or packeted lines at temperatures sufficiently high so that thepumps can handle the molten materials. Such asphalts are customarily andcommercially shipped by tank car, tank truck, barge, and in metal drums.If the asphalt has a very high softening point, as is the case with manyoxidized coating asphalts, the tanks or barges are equipped withinternal heating coils and the tanks can also be insulated so that it iseasy to discharge the asphalt in liquid form from its shippingcontainers. In many instances the oxidized coating asphalts of 165 to180 F. softening point or higher are frequently packaged in fiber drumsor other packaging material having an internal clay-resin,resin-silicone, or clay-silicone composition lining which subsequentlypermits peeling the drum from the asphalt, provided the pack- ;agingmaterial has sufficient strength to permit stripping the material fromthe asphalt without tearing. In other instances the asphalts are shippedin thin metal drums of 24 gauge or lighter and the drums are destroyedor only used once for the purpose. All of these are effective startingmaterials for high softening point asphalts but are sometimes notsatisfactory for lower consistency asphalts, i.e., 80 -l40 F. softeningpoints (ASTM D-36).

Considerable effort has been made in the past to employ low cost systemsfor packaging paving asphalts which are generally of lower softeningpoints. Treated (coated) paper bags have been attempted for this purposebut are not satisfactory. Such bags were coated on the inside or elsethebags themselves were paper bags which were reinforced or laminatedwith their interiors being plastic films. Practically all regular pavinggrade asphalts have from 70 to 95% of oily constituents in admixturewith a dispersion of 5 to 30% asphaltenes. The oily constituents have atendency to exude from the asphalt into the container material so thatif paper bags filled with asphalt are stacked one upon the other, theoily. constituents work through the paper and the bags tend to becometacky and stick together. Additionally, in attempting to empty theasphalt from the paper containers at the mixing plant at ambienttemperatures, the asphalt is so soft and sticky that it is practicallyimpossible to separate the paper from the asphalt. Particularly with thesoft paving grade asphalts, the oil exudation is a problem and it is notpossible in a practical manner to strip the fibrous container from theasphalt.

It is desirable, however, to be able to ship paving grade asphaltcompositions in bags or wrapped in and encased 'in films or sheets ofmaterial which either slow the oil exudation into the containers orwrappers to a minimum or which eliminate such staining and exudationaltogether. In this way, the filled containers will have a minimumtendency to stick together and can be easily handled. Such shipments inbags are especially desirable where paving asphalts are to be used inremote areas where it is not economically feasible to ship the asphaltcompositions from the refinery by railroad tank car, tank truck, orbarge.

It is, therefore, an object of the present invention to devise amaterial for the encasement of paving grade asphalt either in a bag orin a liquid tight wrapper which material resists or minimizes theexudation of the oily constituents of the asphalt. It is a furtherobject of the invention to fabricate a container material fortransporting paving asphalts which container does not become tacky orsticky when the containers are stacked on top of each other, which islow cost and which is non-returnable. It is a further object of theinvention to provide containers for paving asphaltic compositions madeof materials which are compatible with the asphalt and remainincorporated into the asphalt under conditions of ultimate use and whichare easily handled and readily transportable. These and other objects ofthe invention will be come apparent upon a fuller understanding of theinvention.

It has now been discovered that films or sheetings, ranging in thicknessfrom 2 to 6 mils, preferably from 2.5 to 3 mils in thickness, of thepolymeric mono alpha olefins having melt indices (measured at 230 C.) of12 or below, preferably melt indices between about 7 and 10, constitutehighly satisfactory materials into which such asphalts may be encasedfor transshipment to the ultimate users or to mixing plants adjacent tothe ultimate sites of use. Such polymers are typically polyethylene,polypropylene or the copolymer of ethylene with'propylene wherein therelative amounts of ethylene and propylene are either 1 to 10% ofethylene with the remainder being propylene, or 1% to 10% of propylenewith the remainder being ethylene. Larger amounts or more nearly equalamounts of ethylene and propylene produce elastomeric ethylene/propylenecompositions and these are not satisfactory for the intended use becausethey do not have suflicient tensile strength to serve the purpose. Theplastic and plastomeric ethylene/propylene copolymers are suitable formaking the sheeting material which can be used in producing the novelarticles of commerce herein described. Additionally, in order tominimize the conveyance of the oil constituents of asphalt through thepolyolefinic sheeting materials and to insure that the objectionablefeatures of tackiness and stickiness are eliminated, it has been foundto be necessary to use at least two layers of the sheeting material.These two layers of the sheeting material may be in the form of alaminate or they may constitute two separate pieces of sheeting as, forexample a double walled bag. For example, two unlaminated films ofpolyethylene forming a bag is excellent for impeding oil pick-up andtransmission. Laminated two layer polyethylene bags are also highlyuseful but do transmit oily components of paving grade asphalts to asomewhat greater degree than the unlaminated multilayered polyethylenebags. In the preparation of bags that are made of laminated films, anysuitable adhesive may be employed which is ultimately compatible andwill dissolve in the asphaltic material contained in the bag or wrappedin the laminated sheeting. One highly suitable adhesive is the petroleumresins of commerce. These, their method of production, their propertiesand uses in paving compositions are fully described in U.S. Patent No.3,070,570, patented Dec. 25, 1962, which disclosure is incorporatedherein by reference. Other more conventional polyolefin adhesives, ashereinafter described more fully may be used.

In the drawing FIGURE 1 shows, in partial section, a perspective view ofa double-walled bag or encasement containing asphalt.

FIGURE 2 is a sectional elevational view of the package shown in FIGURE1, taken along the line 22.

FIGURE 3 shows, in sectional elevation, a portion of an alternativelaminated double film or sheeting to be used in place of the singlefilms of the double-walled container shown in FIGURES l and 2.

Referring now, in detail, to the features shown in FIG- URES 1 and 2, 2is a container having double film walls 3 and ll of polyolefin sheetingor film with an enclosed air space 4 between the double walls. Asphalt 7is the contents of the bag 2 which is sealed (usually by thermal means)by means of top seal and by means of bottom seal 6. A laminated doublepolyolefin film as shown in FIGURE 3 consists of an outer polyolecn film8 and an inner polyolefin film 9 adhered to one another by means of anadhesive layer or coating 10.

All types of solid or semi-solid (at ambient temperatures) asphalts arecontemplated as being packaged by the laminated or double walledencasement polyolefin films herein described. More specifically, some ofthe standard conventional paving asphalts which may be so packaged areas follows:

The polymers and copolymers of ethylene and/or propylene must have meltindices measured at 230 C. (ASTM D 1238) of less than 12. These are thefilm grade thermoplastics and, in the case of polyethylene, theygenerally have a number average molecular weight in excess of 30,000and, in the case of polypropylene, these film grade polymers have anumber average molecular weight generally in excess of 100,000. In thecase of the plastic or plastomeric ethylene/ propylene copolymers, it isdifiicult to ascribe a precise minimum number average molecular weightbecause this will vary depending upon the relative amounts of ethylene/propylene employed in producing the copolymer. Sufiice it to say,however, that the melt index of the ethylene/propylene copolymers,measured at 230 C., must be less than 12 and that the olefinic monomerspresent in the lesser amount should not exceed of the total olefinicmonomeric reaction mixture. All of these polymeric materials arestandard articles of commerce and it is not necessary to go into thedetails of their methods of manufacture in adequately describing thepresent invention. Suflice it to say that large commercial plants areinoperation today and that millions of pounds of these materials invarious forms, including the film form, are commercially available.

One of the chief advantages of the use of these particular polymers andcopolymers of the mono alpha olefins lies in the fact that there is nonecessity or need for separating or attempting to separate the wrapperor bag from its asphaltic contents once the packaged material has beenshipped to or near the plant of the ultimate user. The entire package,container and contents, are subjected to sufficiently high meltingtemperatures to obtain a homogeneous admixture to serve as aggregatebinder. The multilayered bags or wrappers generally constitute films ofabout 2 mils thick although thicker sheetings may be employedparticularly where a multi-layered laminate is to be employed or Wheretwo or more non-laminated sheetings are to be employed as an unbondeddouble walled bag or wrapper for the asphaltic compositions. Inpreparing laminates, it is possible to use films having a thickness of 1mil down to 025 mil and to build them up to the desired 2 mil-4 milthicknesses by multiple layering. As previously mentioned, petroleumresins may be employed as the adhesive serving to adhere or laminate twoor more film materials together where it is desired to employ laminatedfilms as the container materials. Other suitable adhesive coatings whichare compatible with asphalt and which may be used in preparing filmedsheeting laminates are the following: ethylene-vinyl acetate copolymercontaining from 5% to 40% vinyl acetate and prepared by conventionalprior known methods (See U.S. Patents 2,200,429 and 2,703,794), withoutor with from 5 to 25 wt. percent of the final composition being paraffinwax, chloroprene, rubber cements and the like. Extruded polypropylene infilm form can be treated electrostatically or by flame oxidation afterwhich a film of polyethylene (extruded) is laid in contact therewith at550 to 600 F. and thereafter cooled. Such a laminate is suitable to useas bagging material with the polypropylene or ethylenepropylenecopolymer layer preferably being in contact with the asphalt. Thesheeting in direct contact with the asphalt may be any one of the threeabove mentioned polymers or copolymers, namely, polyethylene,polypropylene, or the plastic or plastomeric copolymer of ethylene withpropylene, preferably polypropylene or the ethylene-propylene copolymer.Other sheetings either in laminated form or as a separate sheet or wall(double or triple walled) of the bag may be of the same material whichis in contact with the asphalt or it may be one of the other twomentioned material s. Thus, the inner or contact material may bepolyethylene or polypropylene and the outer material may be a film ofpolypropylene or polyethylene respectively. Similarly, the internal filmmay be the ethylene/propylene copolymer and the outer material eitherpolyethylene or polypropylene. Double walled containers of polyethylene,polypropylene, or the copolymer may be employed. Polyethylene is bestfor use in the outer wall since it has the highest strength. The othermaterial has the highest oil resistance and may be used as films of 0.25mil to 0.5 mil thicknesses. One of the big advantages of the use ofthese bags lies in the fact that the ultimate user, i.'e., the mixingplant adjacent the site of ultimate placement of the asphalt compositionsimply has to add the entire bag, wrapper and contents, to a 'melterwhich-is equipped with an agitator and to maintain the temperature ofthat melter at a temperature above the softening point of the asphaltand above the softening point of the polyolefinic bagging material sothat the wrapper, or bag, and its contents are both reduced to a moltenstate and thoroughly mixed. To the extent that polyolefin is thusincorporated into the asphalt, its paving properties are altered andimproved. This temperature will vary depending upon the softening pointof the particular paving or industrial asphalt employed and dependingupon the particular olefinic polymer and/or copolymer employed in thewrapper or bag. Generally, temperatures of the order of about 275 F. upto about 550 F. are sufficient to accomplish this desired result. Theaddition of the olefinic polymers or copolymers to the asphalt tends tolend bonding strength to the asphalt composition. (See U.S. Patents3,144,423 and 3,144,424 granted Aug. 11, 1964.) As a further aid in theuniform dispersion of the polymers or copolymers into the moltenasphalt, it is possible to initially incorporate into the asphalt at therefinery or to incorporate into the plastic polymeric sheeting a smallamount of a plasticizer, such as tricresyl phosphate, at least to theextent of its solubility in the asphalt, i.e., up to about 2 wt. percentbased on the total admixed bag and contents. This aids in thedissolution or solvating or" the polymeric wrapper or container materialinto the asphaltic composition at the mixing plant and aids in quicklyproducing a homogeneous mixture of the bags or Wrappers and theirasphaltic contents.

The following examples are given by way of illustration but are notintended to limit the invention thereby.

Example 1 Polyethylene Film Oil Tackiness Package Thickness TransferSuitability Single Wall, 2 mils Severe. Severe. Unsatisfactory. Singlewall, 4 milsd0 Do. Single wall, 6 mils Severe Moderate... Marginal.Double wall, 2-2 mils Moderate... None Satisfactory.

Example 2 A similar grade of paving asphalt as that described in Example1 was packaged in bags which were made of a laminate of 0.75 milthickness of polyethylene film or sheeting bonded to a film ofpolypropylene or" a thickness of 0.25 mil, the two layers being bondedto one another with an adhesive available commercially for variousperiods of time up to 150 days at temperatures of 110 and 150 F., undera loading of 10 lbs. per square foot. The total thickness of thelaminate was approximately 1 mil and only slight tackiness resulted forover twice the storage period used in the case of polyethylene alone asa single walled 2 mil container, which showed severe tackmess.

Having now thus fully described and illustrated the invention, what isdesired to be secured by Letters Patent 1. A package consistingessentially of paving asphalt, having a softening point of between aboutF. and about F., enclosed within a multilayered incasement, each layerbeing a thin flexible continuous self-sustaining poly alpha olefin filmhaving a melt index below about 12 when measured at 230 C., and beingselected from the group consisting of polyethylene, polypropylene andthe plastomeric or plastic copolymer of ethylene with propylene, onecomonomer being present in an amount of between about 1% and about 10%,the remainder being the other comonomer and wherein the poly alphaolefin becomes, upon heating, homogeneous with the paving asphaltcontained therein.

2. The package as in claim 1 wherein the multilayered incasement is adouble walled bag, both walls being polyethylene.

3. A package as in claim 1 wherein the incasement is a double walledbag, one layer being of polyethylene and the other layer being a film ofthe copolymer of ethylene with propylene.

4. A package as in claim 1 wherein the incasement is a double walledbag, one layer being of polypropylene and the other layer being a filmof the copolymer of ethylene with propylene.

5. A package as in claim 1 wherein the multilayered incasement is adouble walled bag both walls being at least a two-ply laminate, one filmlayer being polyethylene and the other film layer beingethylene-propylene copolymet.

6. A package as in claim 1 wherein the multilayered incasement is adouble walled bag, one wall being polyethylene and the other wall beingpolypropylene.

7. A package as in claim 1 wherein the incasement is at least a two plylaminate, one layer being polyethylene and the other layer beingpolypropylene.

8. A package as in claim 3 wherein the laminated films are adhered toeach other by means of an adhesive coating.

9. A package as in claim 7 wherein the incasement is a double walled bagboth walls being at least a two-ply laminate.

TABLE Type and Thickness l Days Temp, Oil Transfer Tacklness PackageSuit- F. ability 1 layer 150 Moderate Slight Satisfactory. 2 layers(double bag) 2g 58 None None Do.

Do 150 150 Trace do D0. Polyethylene:

2 mil, 1 layer 70 150 Severe Severe Unsatisfactory.

2-2 mil, double wall g; }Moderate Very slight Satisfactory.

1 First four runs employed a laminate film (layer) of polyethylene (0.75 mil thickness) adhered to polypropylene (0.25 mil thickness).

References Cited UNITED STATES PATENTS 2,721,691 10/ 1955 Makrauer 229552,762,504 9/1956 Sparks et al. 206-84 2,914,238 11/1959 Clark 206-84 X2,919,059 12/ 1959 Sporka. 2,956,723 10/ 1960 Tritsch. 2,983,704 5/ 1961Roedel. 3,204,825 9/ 1965' Underwood 22955 X FOREIGN PATENTS 660,635 4/1963 Canada.

JOSEPH R. LECLAIR, Primary Examiner.

THERON E. CONDON, Examiner.

I M. CASKIE, Assistant Examiner.

